explanation of hair dryer itch relief

[JeffC11]

I'm in the midst of the second significant bout of Grover's Disease in the last 8 or ten years.  Normally, I try to be good about moisturizing as winter heating season approaches, but I was busy and a bit lax this year and then developed Grover's again.  I've been looking at posts here and elsewhere and have tried the heating (briefly to the point of being painful) method to stop itch that I'd read about on several forums.  Fortunately, I found that it really works and without fail to stop the intense itching of the Grover's Disease spots.  I am a medical school Professor of Neuroscience and I remembered that itch and pain fibers are both carried by small diameter axons, so did some scientific literature research to see what might be known about the relation of itch (pruritis) and pain (nociception) sensitivity and found that it is well established that heat (and extreme cold) induced pain inhibits itch.  The mechanism is not fully known, but it is clear from the scientific evidence that the neural inhibition occurs in the central nervous system (spinal cord or the brain) where the itch and temperature induced pain pathways converge.   I use the hair dryer on high and a couple of inches away from a Grover's spot, then heat the spot to the point where I just begin to feel pain for a second or two.  That or one repetition just wipes out the itching for quite a while.  It's enough to just take this to the point of feeling heat-iduced pain briefly (no point or need to create a burn). This method was recommended in other posts and thanks to using it I was able to get great sleep last night.  I hope this partial explanation of the neural basis for the phenomenon helps to encourage others to try the hair dryer anti-itch technique to see whether it might be as helpful in inhibiting the itch of Grover's Disease spots.  

[Mgiseburt1945]

Wow..I was bite by a spider the other day....very painful....then the itch came....it was driving me nuts...got some relief from ice.....heard about the hair dryer thing...but decided not to try it cause my leg was swollen...and was afraid I'd do more damage then good.....Bye the next day it was so bad couldn't think...got up and tried the hair dryer......and the itching is gone...not just relief but gone...I cannot believe how fast it worked...Did no damage at all..

[jonsevydc]

Buffered Light Enjoyable Scratching  Stops Itching Now  Gently Safely.
Several years ago I got tagged by what I think was a brown recluse spider, judging from the protracted, necrotic reaction. Late in the healing process, the intense itching was waking my up at night. I did not want to irritate or infect the skin, and I am not disposed to drugs, so I reached down under the blanket and scratched through the sheet - taking care not to move the sheet across the skin. The sheet was a buffer that prevented damage to the skin.
It felt heavenly, and after a couple minutes I stopped to go back to sleep. The itch returned after just a few seconds. So I returned to my buffered, light, enjoyable stroking for another 2-3 minutes. The itch was gone longer, perhaps 15 seconds, but much longer than the first time.
After another 2-3 minutes of buffered, light, enjoyable "scratching" through the sheet, I stopped and waited for the itch to come back. It didn't come back for at least 5 minutes while I wondered why the body would make one want to scratch, and why my light, enjoyable, buffered scratching would make the itching go away. Why is the body "telling" us to scratch?
My conjecture is that scratching/stroking accelerates lymphatic and venous flow through the itching area, pumping away waste products, and bringing nutrition and oxygen. I always massage toward the heart to protect and activate the thousands of tiny one-way valves in the veins and lymphatic ducts, so my scratching was primarily in that direction out of habit.
Like any other hunger, when the area's itching demand for cleaning, feeding, and oxygenation are satisfied, the call to action goes away for hours.
I have used this technique many times since then, with the same results. I used it on my 94 year old, institutionalized mother whose legs were covered with stasis dermatitis rash, exacerbated by occasionally frantic scratching. Various salves and, I assume, systemic pharmaceuticals had been tried without success. The technique was successful, although I'm sure that pharmaceutical experiments continued at the same time and I cannot claim that the buffered stroking was the only contributor to the long-term resolution that she enjoyed.
I created an acronym to help her learn the technique while her mind was still relatively clear: B.L.E.S.S.I.N.G.S.
Buffered Light Enjoyable Scratching  Stops Itching Now  Gently Safely.
I have recently tried the hair dryer, and found some relief with that, too. The high heat settings that are advocated here and elsewhere are somewhat worrisome to me, and I am hesitant about  recommending them to those not mature and in full control of their faculties. I found BLESSINGS more enjoyable and relaxing, and the relief again lasting.

[maatson]

While it is well known that both itch and pain fibers carry similarities it was no surprise that the heat source helped you. However it is worth remembering that heat can precipitate Grover's disease on a long term basis.It is indeed an innovative method for itch relief but take care.
My good wishes.